The present invention relates to apparatus for sealing the foldable flaps of cartons by applying a self-adhesive tape material along the edges of the flaps, and more particularly to a belt tracking and tensioning arrangement for a belt arrangement for moving the carton through the apparatus.
In the packaging industry, corrugated and fiberboard cartons have been used for many years and various machines have been developed which are capable of sealing such cartons either by glueing the flaps, taping the flaps, or by stapling or otherwise providing fasteners to maintain the flaps in a closed position. Many of these machines are designed to accept cartons of random width and height by providing various types of means to control the transverse movement of the side arm assemblies associated therewith and the vertical movement of the top sealing means. An example of such a machine is disclosed in U.S. Pat. No. 4,079,577, having the same inventive entity and assignee as the present invention.
The present invention is directed to the endless belt arrangements associated with the side arm assemblies of such machines. The side arm assemblies function to contact the sides of the carton and move same through the machine, whereupon the flaps are sealed. The side arm assemblies may either be manually or automatically adjusted to accomodate cartons of random width dependent upon the particular machine. In either case, the side arm assemblies include a pair of longitudinally spaced rollers about which an endless belt is journalled for movement therearound. A motor is provided in communication with one of the rollers to rotate the roller and consequently drive the belt. The present invention is particularly directed to an arrangement to maintain tension in the endless belt and to maintain the belt on the rollers. If the rollers are slightly non-parallel or if the endless belt is not uniform, it will cause the belt to be in greater tension in one area than another. This unequal tension on the belt tends to cause the belt to move in one direction or the other. If the belt does not achieve a position wherein the tension forces are in balance, it will run off one end of the roller. It is known to provide adjustment means to skew one of the rollers so as to change its axis of rotation to compensate or balance the tension forces on the endless belt.